## Bounds on the minimum distance of linear codes

### Bounds on linear codes [204,12] over GF(2)

 lower bound: 94 upper bound: 96

### Construction

```Construction of a linear code [204,12,94] over
GF(2):
:  [8, 1, 8] Cyclic Linear Code over GF(2)
RepetitionCode of length 8
:  [4, 1, 4] Cyclic Linear Code over GF(2)
RepetitionCode of length 4
:  [4, 3, 2] Cyclic Linear Code over GF(2)
Dual of the RepetitionCode of length 4
:  [8, 4, 4] Quasicyclic of degree 2 Linear Code over GF(2)
PlotkinSum of  and 
:  [16, 5, 8] Linear Code over GF(2)
PlotkinSum of  and 
:  [63, 7, 43] "BCH code (d = 43, b = 1)" Linear Code over GF(2^2)
BCHCode over GF(4) with parameters 63 43
:  [189, 14, 86] Linear Code over GF(2)
ConcatenatedCode of  and 
:  [189, 6, 86] Linear Code over GF(2)
CodeComplement of  with 
:  [189, 5, 86] Linear Code over GF(2)
Subcode of 
: [3, 2, 2] Cyclic Linear Code over GF(2)
CordaroWagnerCode of length 3
: [63, 4, 47] "BCH code (d = 47, b = 1)" Linear Code over GF(2^2)
BCHCode over GF(4) with parameters 63 47
: [189, 8, 94] Linear Code over GF(2)
ConcatenatedCode of  and 
: [189, 13, 86] Linear Code over GF(2)
The Vector space sum:  + 
: [205, 13, 94] Linear Code over GF(2)
ConstructionX using   and 
: [204, 12, 94] Linear Code over GF(2)
Shortening of  at { 205 }

```

### From Brouwer's table (as of 2007-02-13)

```Lb(204,12) = 94 is found by shortening of:
Lb(205,13) = 94 EB1

Ub(204,12) = 96 follows by a one-step Griesmer bound from:
Ub(107,11) = 48 follows by a one-step Griesmer bound from:
Ub(58,10) = 24 follows by a one-step Griesmer bound from:
Ub(33,9) = 12 He
```
###### References
EB1: Y. Edel & J. Bierbrauer, Some codes related to BCH codes of low dimension, preprint, 1995.

He: P.W. Heijnen, Er bestaat geen binaire [33,9,13] code, Afstudeerverslag, T.U. Delft, Oct. 1993.

### Notes

• All codes establishing the lower bounds were constructed using MAGMA.
• Upper bounds are taken from the tables of Andries E. Brouwer, with the exception of codes over GF(7) with n>50. For most of these codes, the upper bounds are rather weak. Upper bounds for codes over GF(7) with small dimension have been provided by Rumen Daskalov.
• Special thanks to John Cannon for his support in this project.
• A prototype version of MAGMA's code database over GF(2) was written by Tat Chan in 1999 and extended later that year by Damien Fisher. The current release version was developed by Greg White over the period 2001-2006.
• Thanks also to Allan Steel for his MAGMA support.
• My apologies to all authors that have contributed codes to this table for not giving specific credits.

• If you have found any code improving the bounds or some errors, please send me an e-mail:
codes [at] codetables.de

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